A fluidized bed reactor (FBR) is a type of reactor device that can be used to carry out a variety of multiphase chemical reactions. In this type of reactor, a fluid (gas or liquid) is passed through a granular solid material (usually a catalyst possibly shaped as tiny spheres) at high enough velocities to suspend the solid and cause it to behave as though it were a fluid. This process, known as fluidization, imparts many important advantages to the fluidized bed reactor. The fluidized bed reactor can thus be used in many industrial applications. Fluidized bed reactors are often used to produce gasoline and other fuels, along with many other chemicals. Many industrially produced polymers are made using fluidized bed reactor technology, such as rubber, vinyl chloride, polyethylene, styrenes, and polypropylene. Fluidized bed reactors are used in various utilities, for example in nuclear power plants and water and waste treatment settings; fluidized bed reactors are also used for coal gasification. Fluidized bed reactors used in these applications allow for processes that are cleaner and more efficient than previous standard reactor technologies.
In conventional fluidized bed reactors, an internal cyclone is often used to separate fine particles from the gas that moves upwards in the fluidized bed reactor during its standard operation. The advantage of such an internal cyclone over a cyclone that is located outside the reactor is that the internal cyclone can be heated up to the process temperature by the process gas without the need of an external heat source. Additionally, the inlet of the internal cyclone will not be easily clogged due to the high temperature of the process gas.
The cyclone is often connected to a discharge pipe that is located within the fluidized bed reactor and channels captured particles back towards the bottom of the reactor. The drawback of this type of setup is that the up-flowing fluidizing gas may bypass the cyclone's inlet and enter the internal cyclone via its discharge pipe. Another drawback is that the whole fluidized bed reactor system must be shut down in case the discharge pipe must be accessed and cleaned because it is clogged. Additionally, the removal of captured fine particles from these types of systems is often difficult.
Thus, there remains a need for a fluidized bed reactor with an improved design that allows the cleaning of a clogged discharge pipe while the fluidized bed reactor is still in operation. The present invention addresses this need.